Q: I registered my domain several years ago with the hopes of promoting my business on the Internet. However, since that time, I've received letters from the attorney of a company that claims they own the trademark for the name I used when registering my domain. They've even contacted the registrar, and my domain has been placed in trademark dispute and is currently inaccessible. Can they do this?

A: I am certainly not an attorney, so I'll leave the question of "Can they do this?" to the legal eagles. However, it appears the company disputing your use of a domain name that may cause confusion with its registered trademark has already been successful at restricting your access to the domain.

Actually, this is not as uncommon an occurrence as one might think, and it all stems from the differences between a domain name and a registered trademark. According to the U.S. Patent and Trademark Office (USPTO), a trademark or service mark is "a word, phrase, symbol or design, or a combination of words, phrases, symbols or designs, that identifies and distinguishes the source of the goods of one party from those of others." A service mark is the same thing as a trademark, except it "identifies and distinguishes the source of a service rather than a product."

There are many misconceptions about trademarks and service marks and the level of protection provided for them under the law. One of the first misconceptions is that a trademark is all-encompassing. In fact, trademarks and service marks are filed under a specific class or classes. (For a complete list of eligible classes, visit the "International Schedule of Classes of Goods and Services" at the USPTO Web site.) There are 45 classes to choose from when filing for a trademark or service mark. Companies can file under one class or multiple classes depending on the nature of their product or service.

For instance, if a company has a registered trademark under class 15, musical instruments, another company using that same name in the pursuit of doing business in the category of musical instruments would potentially cause confusion in the marketplace and infringe upon a registered trademark. However, if a company does business within a different class, say class 1, chemicals, the potential for confusion would be extremely unlikely.

You could have minimized your potential for infringement by conducting a trademark search prior to registering your domain. Such a search can be conducted at the USPTO's Trademark Electronic Search System (TESS). This would have provided you with information regarding companies that held trademarks for the name you were thinking of registering as a domain and what classes they're protected under.

If there were no conflicts, then you would have registered the domain you selected and begun the process of applying for a trademark. Because the domain you initially registered is now in dispute, you have two choices. If you decide you want to fight to keep your domain, you'll need to contact an attorney and discuss all your options at this point. Your other choice would be to give up the fight now, register an alternate domain and start conducting business on the Web again.

If this is what you decide to do, I'd recommend hiring a patent attorney to prepare and file the trademark or service mark application. You can do it yourself, but the process can be very time-consuming and tricky. To find a patent attorney, you can use tools such as Lawyers.com, a searchable database of lawyers.

If you're daring and want to embark upon this undertaking yourself, there are a variety of resources on the Web where you can turn for help. The first is at the USPTO Web site. You can get all the facts about how to apply for a trademark at their resource page, "Basic Facts About Trademarks". You can also start the application process online at the USPTO Trademark Electronic Application System (TEAS). Prior to starting though, you may want to visit MarksOnline, an intellectual property portal that has a impressive collection of information and resources related to trademarks, patents, copyrights, and general intellectual property issues.

Charles Fuller is the vice president, development of Entrepreneur.com. As our Web site's founder and first employee, Chuck has been instrumental in contributing to the site's design, marketing and business development.